1. Field of the Invention
The present invention relates to an RFID (Radio_Frequency_IDentification) tag which exchanges information with an external device without contacting the device. Among people skilled in the field of the art, “the RFID tag” used in the present invention is also called as “a wireless IC tag.”
2. Description of the Related Art
In recent years, various RFID tags have been proposed that exchange information with an external device represented by a reader and writer by a radio wave without contacting the external device (for example, see Japanese Patent Application Publications Nos. 2000-311226, 2000-200332 and 2001-351082). As a kind these RFID tags, one that has a configuration in which an antenna pattern for radio communication and a circuit chip are mounted on a base sheet made of a plastic or a paper is proposed. For such types of RFID tags, various applications are devised. For example, the RFID tag is attached to an article or the like to exchange information about the article with an external device for identifying them.
Of applications for the RFID tags, there is one included in which an RFID tag is attached to an article whose shape can be easily changed like clothes. In such application, one major problem is that the circuit chip receives a bending stress as the circuit chip is not easily bent while the base sheet is easily bent, causing the circuit chip to be cracked or peeled off. Conventionally, there have been proposed techniques in which the circuit chip including the periphery around the circuit chip is covered with a hard reinforcing member to prevent shape changing of the RFID tag from reaching the periphery around the circuit chip, thereby decreasing a bending stress applied to the circuit chip.
However, with such technique using the reinforcement member and the like described above, an end of the reinforcement member or the like crosses the antenna and a bending stress is concentrated at the cross point to cause a break of the antenna.